Deep venous thrombosis (DVT) comes about when a blood clot (thrombosis) forms in a vein, usually one that's located deep within the leg. The symptoms of DVT include swelling, pain, tenderness to touch, redness, and feelings of warmth at the site of the DVT.
Quite similar symptoms can be felt if a vein near the surface of the skin becomes inflamed, infected, or blocked. This disorder, however, termed superficial phlebitis, is not nearly so serious as a DVT. DVTs present a much graver problem than do instances of superficial phlebitis because all or part of a DVT's blood clot can suddenly break off at any time, travel through the bloodstream, and finally end up lodged inside a pulmonary artery. This blockage of the blood supply to the lungs is a dangerous condition known as a pulmonary embolus (PE).
A PE is fatal about 25 percent of the time, and death is frequently sudden. About 2 million Americans suffer a DVT each year, and these clots generate most of the PEs that cause the deaths of more than 50,000 people a year in the U.S.
DVTs are treated with anticoagulants, which help to prevent further enlargement of the clot. Superficial phlebitis in a vein near the skin's surface rarely causes a PE, and so will usually not require anticoagulation therapy; instead, superficial phlebitis can be managed merely by elevating the leg, applying local heat, and administering a nonsteroidal anti-inflammatory drug (NSAID) to combat the pain and inflammation.
But since the symptoms of DVT can so closely resemble those of superficial phlebitis, you should always contact your doctor if you ever experience painful swelling, tenderness to touch, redness, or feelings of warmth in one of your legs. If it turns out that you do have a DVT, you will require immediate treatment to ward off a possible PE.
Although most people are not at risk for DVTs before age 60, the following conditions and situations can raise the risk of having a DVT at an earlier age:
- pregnancy
- certain types of cancer
- hospitalization, especially for surgical procedures
- medications, including birth control pills (especially in smokers), hormone replacement therapy, erythropoietin, and tamoxifen
- long periods of bed rest
- protracted episodes of sitting still on airplanes or in cars
- inherited abnormalities that can lead to increased clot formation
As is the case with so many disorders, DVTs are more common in those who smoke or are obese.
The risk of developing a DVT is especially high in those who have just undergone a neurosurgical procedure or have had surgery involving the hip, the knee, or the pelvis. Due to a patient's necessarily diminished physical activity after these particular procedures, the risk of DVT can linger throughout the recovery period.
If you develop a DVT before age 50, particularly if other family members have also had them, ask your doctor to check for an inherited clotting abnormality.
The greatest risk for a DVT, however, is a prior DVT or PE. Accordingly, anticoagulation is continued for a minimum of 3 months after a DVT, and even longer in those who've had one or more prior DVTs or have other conditions that increase their risk of DVT. Some experts advocate prolonged anticoagulation treatment even after a single DVT episode. Your doctor will have to decide how long to continue your anticoagulation therapy, balancing the risks of another DVT against the danger of bleeding caused by the anticoagulant.
The most important carry-home message here is, if you ever develop the symptoms of a DVT, contact your doctor promptly so that you can be started immediately on anticoagulants, thereby reducing your likelihood of a life-threatening PE.
